One objective of the proposed research program is to draw conclusions about the structure and organization of normal memory through analysis of the amnesic syndrome in man. The amnesic syndrome will be studied in psychiatric patients receiving electroconvulsive therapy (ECT) for depression, persons sustaining concussive head trauma, and aged persons. A second objective is to determine by prospective and retrospective follow-up studies how long after ECT memory problems persist. Newly developed tests of remote memory will be used to examine prolonged retrograde amnesia, and tests of anterograde amnesia will also be used to examine hypotheses concerning state-dependent learning and the susceptibility of amnesia and "reactivated" old memories.